During outdoor activities such as camping, a portable heater having a simple structure is considered as an appliance for easily heating water held in a container, canned goods or the like for the purpose of cooking precooked foods or making tea or coffee. Such a portable heater supports the container, the canned goods or the like, and, for instance, a fuel tank, a burner and an ignition means are arranged at the bottom of the heater. The emission and ignition of gas from the burner are carried out by the operation of an ignition lever, and heating is effected by combustion using a burner that is relatively small about the size of a gas lighter or thereabouts.
In a heater that effects heating by the combustion of gas, it is necessary to interrupt the emission of gas if flames go out for any reason during the combustion. To this end, several types of an extinguished-flame safety device have already been put forward, which interrupt the discharge of gas when flames go out.
Moreover, heaters, such as a gas stove for domestic use and a stove which uses kerosene, are usually equipped with an overturn safety device for automatically extinguishing flames in view of the prevention of a fire when the stove falls as a result of an earthquake or the like, and several types of mechanisms used as such a device have also been put forward.
In a portable heater such as previously mentioned, when a container to be heated is warmed by a burner, an internal pressure of the container body rises owing to an increase in temperature of the contents of the container if the container is heated while it is sealed. Eventually, several problems may arise which are ascribed to the rupture of the container during heating or the spewing-out of the contents of the container when the container is opened. Hence, it is necessary to maintain the container open to the atmosphere when being heated.
In view of the foregoing drawbacks, the object of this invention is to provide a safety device for use with a portable heater which automatically bores a hole in a container body when the container is heated.
Another object of this invention is to provide a safety device for use with a portable heater that ensures easy opening of the container and allows ignition operation to be performed only after the container is opened and also releases the container from its closed state when it is heated.
By the way, in the case of a portable heater, in order to ascertain the ignition of gas after ignition operation, it is troublesome for a user to lean over and visually check flames through a verification window. The extinguished-flame safety device of some portable heaters may require a much longer time to check the ignition of gas. Hence, it is necessary to make the verification of ignition easy to perform. The portable heater also encounters a problem that a user may burn his hand or spill the contents of the heater when he inadvertently makes contact with a high temperature section, because the user is not aware of whether or not the heater itself becomes hot after heating has been completed.
For this reason, another object of the present invention is to provide a safety device that facilitates a check to see whether or not ignition is effected and attracts a user's attention when handling a heater by indicating the temperature.
Even a portable heater with a simple structure as mentioned above suffers from insufficient heating which will occur when flames are unexpectedly extinguished by wind or the like, because the volume of a fuel tank is limited. Thus, there are demands for an extinguished-flame safety device that interrupts the discharge of gas when flames unexpectedly go out and an overturn safety device that automatically extinguishes a flame when the heater falls over. However, a conventional safety device used with a heater which employs town gas is complicated in structure, and also adds to the cost of the heater, thereby rendering the safety device disadvantageous. Hence, there is also a demand for these safety devices to have a simplified structure.
To this end, another object of this invention is to provide an extinguished-flame safety device or an overturn safety device which is applicable to a simple and small-sized portable heater.